At Stockwell Tube station in south London, Metropolitan Police firearms officers were congratulating themselves on a job well done. They believed they’d just shot dead a failed al-Qaeda suicide bomber, Hussain Osman.
His body lay slumped in a seat on a stationary Northern Line train at platform two, his denim jeans and jacket covered in blood. Fearing that he was carrying a device, the officers withdrew to the central hub of the Underground station and called in an explosives officer to check and make the scene safe.
